Production of lubricants



United States Patent PRODUCTION or LUBRICANTS larold M. Fraser, NewOrleans, La., assignor, by mesne assignments, to Shell DevelopmentCompany, San Francisco, Calif., a corporation of Delaware Drawing.Original No. 2,380,960, dated August 7, 1945, Serial No. 449,014, June29, 1942. Application for reissue May 6, 1957, Serial No. 657,994

Claims. (Cl. 252-36) Matter enclosed in heavy brackets [Ii appears inthe iriginal patent but forms no part of this reissue specifiration;matter printed in italics indicates the additions nade by reissue.

The present invention relates to the production of ubricants, and moreparticularly to lubricants containing I. lubricant base as, for example,mineral oil or other :quivalent oils well known in the art, and [amaterial 'urnishing a hydrogenated ricinoleic acid radical: statedlilferently, a material containing the hydroxy fatty acid radical ofhydrogenated ricinoleic acid, said fatty acid 'adical being present inthe lubricant, and particularly a grease in the form of] a soap [or amixture of a soap 1nd a fatty acid] of hydrogenated castor oil,otherwise :ermed IZ-hydroxy-stearic acid.

In one form of the present invention, it is desired to arovide greaseshaving incorporated therein a metal soap of l2-hydroxy-stearic acid,[although in lieu thereof the grease may have incorporated therein asoap in which the hydroxy fatty acid radical of hydrogenated ricinoleicacid is coupled to an organic base] as hereinafter more fully set forth.[The fact that the hydroxy fatty acid of 12-hydroxy-stearic acid may becoupled with either an organic radical or a metal radical indicates thatit is the said hydroxy fatty acid radical which imparts thecharacteristic chemical and/ or physical properties to greases havingpresent materials containing said radical] Some of the materials,including those set forth furnishing 12-hydroxy-stearic acid or thehydroxy fatty acid radical of hydrogenated ricinoleic acid, or what maybe termed the hydrogenated ricinoleic acid, are soluble in the oilcomponent of the lubricant grease, and therefore require no blendingagent for their incorporation in the grease. [As an example of such amaterial, there is set forth the lead soap of IZ-hydroXy-stearic acid,said soap being soluble in the mineral oil or other oil component of thegrease] However, other materials containing the hydroxy fatty acidradical of hydrogenated ricinoleic acid are only slightly soluble orsoluble with diificulty in mineral oils and other oils at lowtemperatures such as ordinary room temperatures, and therefore, it isneces- 7 sary to provide for the permanent dispersion or blending ofsuch material including [hydrogenated castor oil, 12- hydroxy-stearicacid, and] soaps of '[hydroxy stearic acid, including]12-hydroxy-stearic acid with the mineral and/or vegetable and/or animaloil constituent of the grease. In other words, when the materialcontaining the hydroxy fatty acid radical of hydrogenated ricinoleicacid is soluble with ditliculty, or only slightly soluble in a lubricantbase, it is desirable and, in most cases, necessary, to provide acarrying agent adapted to permanently disperse said material in thelubricant base. Examples of metal soaps only slightly soluble in themineral oil base are the aluminum soaps of hydrogenated ricinoleic acidI, and the aluminum, lead and sodium soaps of the polyhydroxy stearicacids. When the 12-hydroxy-stearic acid and/ or hydrogenated castor oilitself is incorporated in the mineral oil base, it is also desirablethat a blending Reissued Apr. 15, 1958 ice agent be present, andparticularly the blending agent comprising the aluminum soaps of thehigher saturated fatty acids such as aluminum stearate, although othermetal soaps may be used as the blending agent].

Many of the greases, particularly the soda base greases, whensubstantially dehydrated have a tendency to exhibit a granularstructure. The metal soaps of hydrogenated ricinoleic acid, andparticularly the metal soaps of hydrogenated castor oil as typified bythe aluminum soap of hydrogenated ricinoleic acid, function as agranulation inhibitor, thereby producing a grease of extremely smoothconsistency. [Similar results are obtained by incorporating in soda basegreases varying amounts of hydrogenated castor oil itself orIZ-hydroxy-stearic acid. These materials, as previously indicated,function similarly to the metal soaps of hydrogenated ricinoleic acid,since they are the full equivalents containing the essential hydroxyfatty acid radical of hydrogenated ricinoleic acid which is responsiblefor the granulation inhibiting property of said materials] It is desiredto point out it is highly advantageous to incorporate in grease soaps of[hydroxy stearic acid, and particularly the] 12-hydroxy-stearic acid,because said soaps have a low water solubility. For example, the [leadand] aluminum soaps of hydrogenated castor oil or of lZ-hydroxy-stearicacid are substantially insoluble in water. [The l2-hydroxy-stearic aciditself and hydrogenated castor oil function similarly] in accordancewith the present invention, in one of its forms lubricant greases mayhave incorporated therein [a soap of hydroxy-stearic acid, as forexample a metal soap of said acids, and more particularly] a metal soapof hydrogenated ricinoleic acid, said soap being the only soap. Theremay be a single soap of the above character present in the grease or aplurality of different soaps of the above character to thereby form amixed soap base grease. For example, there may be present a mixture ofthe aluminum soaps and the lime soaps of [the hydroxy-stearic acids, andparticularly soaps of the] l2-hydroxy-stearic acid or the grease mayhave incorporated therein an aluminum soap, together with a sodium soapof a hydroxy-stearic acid of the character set forth. For example, theremay be incorporated in the grease in addition to the lead soap ofhydrogenated ricinoleic acid an ordinary soda soap or a soda soap ofhydrogenated ricinoleic acid]. In short, the grease may have present aplurality of soaps, all of which [may be soaps of hydroxy-stearic acid,]or some [of the soaps] may be [soaps of hydroxy-stearic acid, as forexample] metal soaps of hydrogenated ricinoleic acid, and the remainingsoaps may be the ordinary prior art soaps. [The soaps present in thegrease may be those of the monohydroxystearic acids, or those of thepolyhydroxy-stearic acids, or the lubricant having said soaps presentmay also have any of the prior art soaps. Said soaps inherently containbecause of their method of manufacture small quantities to relativelylarge quantities of 12-hydroxy-stearic acid. In the example herein setforth, there is always inherent present in the soap produced at least 3to 6% of the free fatty acid of hydrogenated castor oil, andconsequently greases compounded in accordance with certain of theexamples herein set forth do contain not only the soap ofIZ-hydroxy-stearic acid but the 12-hydroxystearic acid itself, as willbe more fully described hereinafter.]

In accordance with the present invention, certain addition agents may beadded to the grease to produce a smoother texture. Further, thesegreases function to reduce the milling time of the grease after cooling.It is preferred that these addition agents be added to the grease beforepouring.

It is an object of the present invention to produce greases containing amaterial having present the hydroxyfatty acid radical of hydrogenatedricinoleic acid, said radical being present in a soap of hydrogenatedricinoleic acid I, or in hydrogenated castor oil, or in12-hydroxystearic acid itself, or in mixtures of any and all of saidmaterials]. While the 12-hydroxy-stearic acid may be obtained bysaponifying an oil which has been hydrogenated, as for example castoroil, it is obvious that the l2-hydroxy-stearic acid may be produced byother methods. Soaps may be obtained from the lZ-hydroxystearic acid bytreating the latter with [an organic compound or] metal compound.

It is a further object of the present invention to incorporate in agrease in conjunction with [a soap of polyhydroxy-stearic acid and/ or]a soap of 12-hydroxystearic acid, [and/ or lZ-hydroxy-stearic aciditself, and/ or hydrogenated castor oil,] a metal salt of a higherunsaturated fatty acid, and particularly an aluminum salt .of a highersaturated fatty acid, to produce greases novel in the art which possessthe advantages above set forth, and other advantages which will appearfrom fol lowing disclosure.

The present invention will be illustrated by a number of examples, thefirst of which will be directed to the incorporation of an aluminum soapof hydrogenated ricinoleic acid in the lubricant base, said soaprequiring the presence of a dispersing or blending agent for the purposeof permanently blending and incorporating the soap in the lubricatingbase.

Referring to the blending agent, it may be stated that all of thealuminum soaps of the higher saturated fatty acids starting with thosecontaining twelve (12) carbon atoms may be used as the carrier,dispersing or blending agent. The aluminum soaps of the unsaturatedfatty acids carrying more than twelve (12) carbon atoms may also be usedas the carrier agent, but produce softer greases than is the case whenthe aluminum soaps of the saturated fatty acids are used. Instead ofusing aluminum soaps of the higher saturated or unsaturated fatty acidsother metal soaps may be used as the carrier dispersing or blendingagent, as will be apparent to those skilled in the art.

Specific examples of suitable saturated fatty acid soaps adapted to beused as blending agents are:

Aluminum salt of palmitic acid C H O Aluminum salt of myristic acid C HO Aluminum salt of lauric acid C I-1 Aluminum salt of stearic acid C H OSpecific examples of suitable unsaturated fatty and resin acid soapsadapted to be used as blending agents are:

Aluminum salts of the following acids:

Myristoleic acid C H O Palmitoleic acid G -H 0 Oleic acid C1gH3402'Linoleic acid C18H32O2 Linolenic acid C H O- Abietic acid Q C20H30O2Titre 64.5 Sapon. 'No 178 Iodine No 2.57

The hydrogenated castor oil is a solid and has a melting point of about72 C., which indicates that the hydrogenation process has beenpractically carried to completion. The best results in practicing thepresent inven tion will be obtained by producing an aluminum soap ofsubstantially completely hydrogenated castor oil. However, the castoroil may be only partially hydrogenated and still may be used. Stateddifferently, the higher the degree of hydrogenation of the castor oil,the better results obtained when the aluminum soap thereof isincorporated in the lubricant base.

One thousand (1000) pounds of hydrogenated castor oil having theproperties above set forth are mixed with two hundred and eighty (280)gallons of water and charged into a mechanically agitated kettle. Thismixture is heated until the fatty material has melted. Thereafter, asolution of two hundred and five (205) pounds of caustic soda dissolvedin one hundred and seventy (170) gallons of water is run into the kettleslowly, the time consumed in said addition being approximately thirty(30) minutes. Heating and stirring is maintained for approximately two(2) hours until the fatty base has saponified. Thereafter, a solution offive hundred and sixty (560) pounds of aluminum sulphate dissolved intwo hundred (200) gallons of Water which has been heated toapproximately F. is run into the kettle, and the entire mixture agitatedfor a period of time sufficient to allow the aluminum salt to react withthe water solution of the sodium hydrogenated ricinoleate, this usuallytaking, for the quantities above set forth, thirty (30) minutes. Theheating of the mixture is then stopped and the mixture is agitated untilthe aluminum soap has completely separated from the liquid. Thereafter,the liquid solution is drained from the bottom of the kettle. The soapremaining in the kettle is then washed by pumping therein water of theamount of about two hundred (200) gallons, the water being maintained ata temperature of from to F. After stirring for about ten (10) or fifteen(15) minutes, the agitation is stopped and the wash water is drainedfrom the bottom of the kettle. This procedure may be repeated until thealuminum soap of the hydrogenated castor oil is sufficiently pure forcommercial purposes. Usually it is sufiicient if the washing is repeatedthree (3) times.

This white insoluble soap of hydrogenated ricinoleic acid or soap of12-hydroxy-stearic acid also contains at least 3 to 6% of the free fattyacid of hydrogenated castor oil or, stated differently, said soapcontains in admixture therewith at least 3 to 6% of IZ-hydroxy-stearicacid and in many cases a considerably greater percentage is present.Therefore, greases or lubricants having incorporated therein soaps of12-hydroxy-stearic acid also carry varying amounts of l2-hydroxy-stearicacid, and since greases may be produced in accordance with the presentdisclosure carrying up to 50% of soaps of 12- hydroxy-stearic acid, saidgreases inherently carry not only small amounts of l2-hydroxy-stearicacid, but in some cases relatively large amounts of 12-hydroxy-stearicacid. Therefore, in the above example the aluminum soap of12-hydroxy-stearic acid carries at least 3 to 6% of 12-hydroXy-stearicacid. If one-half percent of the soap produced as above set forth isadded to the grease as :set forth in Table II, then the amount ofl2-hydroxystearic acid which will be present will vary between .015 to.03%. If in the composition set forth in Table ll the amount of aluminumsoap of hydrogenated castor oil is increased to 10% as it may well be,then the amount of l2-hydroxy-stearic acid present in the grease willvary from 0.3 to 0.6%. If 50% of the aluminum soap of 12-hydroxy-stearicacid is present in the composition set forth in Table 11, then theamount of free 12-hydroxystearic acid will vary between 1.5 to 3%.

The aluminum salt of hydrogenated castor oil produced as above, containsa considerable quantity of water and, therefore, is pumped through acentrifuge where most of the water is removed. From the centrifuge, themoist aluminum salt of hydrogenated ricinoleic acid is removed to ahammer mill which breaks the salt into small granules. Preferably, thegranules are then placed on trays and introduced into ovens heated withhot air to a temperature of about 200 F. The aluminum salt of thehydrogenated castor oil is allowed to remain in the oven until it isdried, which is usually about twenty-four (24) hours. The dried salt isthen run through a hammer mill adapted to break the salt into such afine flocculent state that substantially all of the salt will passthrough a one hundred (100) mesh sieve.

Instead of using aluminum sulphate, aluminum chloride may be used or anyother Water soluble aluminum salt, the acid radical of which willcombine with the sodium to release the aluminum so that it may combinewith the fatty acid, the sodium salt being water soluble.

Instead of treating hydrogenated castor oil as set forth, for a portionof the hydrogenated castor oil there may be substituted stearic acid orany material having present this constituent. The mixture of thehydrogenated castor oil and the stearic acid containing material may betreated as hereinbefore described in connection with hydrogenated castoroil. However, with the presence of the stearic acid component on theaddition of a water soluble aluminum salt, aluminum stearate is formedin addition to the aluminum soap of hydrogenated ricinoleic acid orcastor oil. In general, the hydrogenated ricinoleic acid may havesubstituted therefor up to fifty percent (50%) of a stearic acidcomponent. For example, instead of treating one thousands pounds (1000lbs.) of hydrogenated castor oil, there may be substituted for thisconstituent a mixture of nine hundred pounds (900 lbs.) of hydrogenatedcastor oil and one hundred pounds (100 lbs.) of a material con tainingstearic acid; or the mixture may contain twenty percent thirty percentforty percent or fifty percent (50%) of a stearic acid component or anyother intermediate percent, as for example twenty-five percent (25%),thirty-five percent (35%), or forty-five percent The amount of stearicacid material which is substituted for a portion of the hydrogenatedcastor oil will vary in accordance with the desired characteristics ofthe final lubricating grease and the use for which it is intended. I

It is desired to point out that the presence of the stearic acidcomponent in the mixture of hydrogenated castor oil and stearic acidfacilitates the cooking operation, that is, the melting of the fattymaterial, and further, produces a product which can be washed andcentrifuged with greater ease than the aluminum soap of hydrogenatedcastor oil itself. This is a decided advantage.

The aluminum salt of the hydrogenated ricinoleic acid containing becauseof its method of production a small quantity of 12-hydroxy-stearic acidor hydrogenated castor oil, together with a metal salt of a saturated orunsaturated fatty acid and particularly aluminum stearate or otheraluminum or fatty acid soap, may be introduced into a lubricant base inany proportion, and particularly in such proportions as are hereinpointed out which function to prevent oil seepage of bleeding and alsofunction to improve the texture of the resulting lubricant, that is,which will prevent the granulation of the lubricant, reduce thegraininess of the lubricant, and in general make the resultinglubricating grease smoother and firmer than would have been the case hadthe material containing the 12-hydroxy stearic acid radical beenomitted.

While it is not desired to be limited to a lubricating base or a greasecontaining any particular percentage of a material containing a soap ofl2-hydroxy-stearic acid [or 12-hydroxy-stearic acid itself, orhydrogenated castor oil] in general it may be stated that the lubricantbase may have said materials including the soaps present in amounts upto of the total weight of the grease. In the more limited aspect of thepresent invention, the aluminum salt of hydrogenated ricinoleic acid,and particularly [castor oil] hydrogenated castor oil, and12-hydroxy-stearic acid may be present in the lubricant or grease inamounts varying between A to 10%, based on the total weight of thelubricating grease, the latter preferably having present other soapssuch as ordinary aluminum soaps, sodium soaps, or the like. Satisfactoryresults have been obtained when the aluminum salt of hydrogenatedricinoleic acid or aluminum salt of 12-hydroxy-stearic acid is presentin amounts ranging from V2 to 5% based on the total Weight of thelubricating grease. [Similar percentages of 12-hydroxy-stearic acid orhy- .rogenated castor oil may also be used, preferably in combinationwith the metal soaps of the saturated fatty acids such as aluminumstearate] It may be pointed out that the solid or semi-solid lubricantsof the present invention having incorporated therein aluminum soaps ofhydrogenated ricinoleic'acid, and especially hydrogenated castor oiland/ or the equivalents thereof, as above pointed out, together withother soaps such as aluminum stearate or sodium soaps, have moredesirable properties than would have been the case had the samelubricant been used without the addition of the herein set forthaluminum soap ofhydrogenated ricinoleic acid, and preferably thealuminum soap of hydrogenated castor oil or their equivalents, as abovepointed out.

As pointed out, instead of using the aluminum soap of hydrogenatedcastor oil, a mixture of the soap and aluminum stearate or other metalfatty acids, especially the metal soaps of the higher saturated andunsaturated fatty acids containing twelve (12) carbon atoms or more, thelatter functioning as a carrier dispersing or blending agent, may beincorporated in a grease or semi-solid lubricant. When the mixture isincorporated in the lubricant or grease usually more of the mixture isused than when the aluminum soap of hydrogenated castor oil isintroduced by itself into the grease. For example, when one-quarter /4)of one (1) percent of the aluminum soap of the hydrogenated castor oilis added to the lubricating grease to produce the desired result, if afifty-fifty mixture of the said soap and an aluminum stearate is usedone-half /z%) percent of the mixture will be added to the lubricant toproduce the same or similar result.

The advantages residing in the present invention will be clear from thefollowing: a regular aluminum stearate grease was made up according tothe following formula:

TABLE 1 Percent Aluminum stearate 7 175 vis. oil at F. (mixed baseparaflin and asphalt oil) 93 The grease was made by dissolvingcommercial aluminum stearate in the oil and heating to about 290300 F.The resulting grease was smooth and clear, but on standing for severaldays, a small amount of oil separated from the grease. The A. S. T. M.worked penetration on the above grease was 357. p

Instead of using 7% of aluminum stearate, a similar lubricating greasewas made up, but there was incorporated therein one-half percent /2%) ofaluminum soap of hydrogenated castor oil. The mixture then comprised:

TABLE II Percent Aluminum stearate Q- 6 /2 Aluminum soap of hydrogenatedcastor oil /:z

vis. oil at 100 F. (mixed base paraffin and asphalt oil) 93 Thelubricant produced in accordance with the mixture of Table II stood forseveral days without any oil seeping therefrom. This indicates theadvantage of having present the aluminum soap of hydrogenated castoroil. The A. S. T. M. worked penetration on the above grease was 346.

It is further desired to point out that when the lubricant set forth inTable I had a small amount of lump rosin added thereto, as for example.06%, the lubricant was very grainy and leaked oil rather badly. Theaddition of the small amount of rosin to the lubricant of Table IIproduced no such result. The lubricant of Table ll with the addition ofrosin was smooth and firm and had an A. S. T. M. worked penetration of333.

The above example indicated that by the addition of a small amount ofthe aluminum soap or hydrogenated ricinoleic acid, and particularlyother soaps, and especially those containing aluminum soaps, that theresulting grease is more stable, and smoother, and firmer, than a greaseof similar characteristics, but in which no aluminum soap ofhydrogenated castor oil is present.

Further, as pointed out, when agents are added in small quantities tomake the grease harder, as for example, rosin, rosin oil, the resultinggrease, despite the addition of the hardening agent, is still smooth andfirm and does not leak oil, provided there has been incorporated in thegrease a small amount of an aluminum soap of hydrogenated ricinoleicacid, or of hydrogenated ricinoleic acid, or lZ-hydroxy-stearic acid,the soap or equivalent being present in amounts varying from one-quarter(Me) to ten percent (10%) and preferably one-quarter 4%) to five percent(5%). The aluminum soap of hydrogenated ricinoleic acid or equivalentmay be present in some cases in greater amounts up to fifty percent(50%) of the total weight of the grease.

It is also desired to point out that those greases having thegranulation inhibitor of the present invention, after being mixed, arepoured into pans of any suitable size, as for example, twenty-four bysixty inches (24 x 60), the depth of the grease layer being about threeinches (3"), and then cooled by blowing first with warm air having atemperature of 125 F. and then slowly reduo ing the temperature of theair to room temperature over a period of eight (8) to twelve (12) hours.

It may be pointed out that it is a general rule that the hardness of thegrease may be increased by increasing the amount of soap present. Inother words, if the grease of Table II has the aluminum stearateincreased from six and one-half percent (6 /2%) to eight (8%), theresulting grease would have a harder consistency than a grease havingmerely six and one-half percent of the aluminum stearate.

The aluminum soap of hydrogenated ricinoleic acid and especially castoroil may be incorporated in a soda soap grease in accordance with thefollowing:

Percent k- IQ NUNNIQQ LAUL It is desired to point out that in the abovecomposition the soap content may be varied to suit the type oflubrication required. In said composition the amount of the sodium soapsmay be materially increased and moreover, the amount of aluminum soap ofhydrogenated castor oil may be increased. It may vary, as pointed out,from one-quarter percent to ten (10%) percent or even, in somecircumstances, less than one-quarter /4 70) of one percent (1%), thishowever being unusual. instead of using in the above compositionaluminum stearate as the carrier dispersing or blending agentotheraluminum soaps of the higher fatty acids may be used as hereinpreviously disclosed. However, the aluminum stearate gives the preferredresults. The amount of blending agent used may vary over a veryconsiderable range depending upon the character of the lubricatinggrease being treated.

In preparing the above, the sodium soaps and the Coastal Pale are heatedin a vessel to which is then added .3 of 1% of the aluminum soap ofhydrogenated castor oil and .2 of 1% of aluminum stearate. The heatingis then continued until the grease melts to a sticky mass. Thereupon,additional oil, that is, the 3600 green cast red oil is added slowlywhile stirring, the mixture being brought to a temperature of about 350to 410 F. The grease is then pumped or poured at a temperature of about350 to 360 F. into pans of any suitable size, the depth of the greaselayer being about three (3) to four 4) inches. The grease is then cooledin a manner similar to that pointed out in connection with previousexamples. The grease prepared in accordance with the above had an ASTMworked penetration of about 310 to 325 and the grease had a meltingpoint of 300 F. The grease did not leak oil and was exceedingly stableduring storage. In the grease prepared without the aluminum salt ofhydrogenated castor oil, there would have been some leakage, and duringstorage, the grease would not have been as stable. This inidcates theadvantages of the present invention.

Further, it is desired to point out that if the aluminum soap ofhydrogenated castor oil was omitted, the grease did not gel properly andthe oil separated from the soap base.

Instead of incorporating the aluminum stearate in the grease in themanner above set forth, the grease may be prepared with the aluminumsoap of hydrogenated castor oil, and another grease may be prepared withthe aluminum stearate. When the two greases have been poured and cooledthey may be then milled together as set forth in Fraser Patent No.2,257,945.

It is desired to point out that the grease is poured at about 350 to 360F., and the grease is cooled from this temperature to approximately F.in twelve (12) hours to thereby produce a transparent grease, the Watercontent of which is less than 25% (1% of 1%).

The [aluminum soaps of hydroxy-stearic acid, and particularly the]aluminum soap of l2-hydr'oxy-stearic acid, this soap being produced byvarious means, but preferably by saponification of hydrogenatedricinoleic acid, is not readily soluble in the lubricant base when usedby itself, but is maintained substantially permanently dispersed whenused with other blending or dispersing agents, such as aluminum soaps ofthe higher saturated fatty acids, or the sodium soaps of the fattyacids, and more particularly the higher saturated fatty acids. Attemperatures between F. and 250 F. and higher, the dispersion of thealuminum soap of hydrogenated ricinoleic acid is substantiallypermanent.

If the aluminum soaps of non-hydrogenated commercial castor oil are usedto replace the aluminum soap of the hydrogenated castor oil in the abovecompounds, the resulting grease is much softer and the oil seeps out. It

may be stated that in general, greases made with the addition of thealuminum soap of hydrogenated ricinoleic acid, and especiallyhydrogenated castor oil, said greases containing other soaps of thefatty acids, soaps of rosin, and the like, are similar in body,exceedingly stable relative to oil separation, and retain theirconsistency better when worked than greases of substantially the samecomposition, but in which there is no aluminum soap of the hydrogenatedricinoleic acid, or more specifically the aluminum soap of hydrogenatedcastor oil.

It may be pointed out that the hydrogenated ricinoleic acid of the12-hydroxy-stearic acid has an OH group present in the chain, and thisis not true of the other fatty acids. It is believed that the manner inwhich the aluminum salt of hydrogenated ricinoleic acid acts in thepresent invention to prevent granulation and seepage of oil is due tothe presence of an OH group in the chain.

mineral oils, in proportion up to 40 to 50%.

[This same hydroxy fatty acid group is present in 12- nydroxy-stearicacid and in hydrogenated castor oil, and these materials whenincorporated in a lubricant would impart the same characteristicchemical and physical properties to said lubricant as when the soaps ofl2-hydroxy-stearic acid are incorporated in the lubricant. As pointedout, the essential structural feature of all of these compounds is thepresence of the hydroxy-fatty acid radical of hydrogenated ricinoleicacid, and therefore the compounds are full equivalents and the soapswhen produced in accordance with the method herein set forth contain insome cases small amounts and in other cases relative large amounts ofIZ-hydrOXy-stearic acid itself] From the above, it can be gathered thatthe aluminum soaps of the other fatty acids are not the equivalent ofthe aluminum soaps of hydrogenated ricinoleic acid as derived fromhydrogenated castor oil.

While it is clear that the amount of carrier or blender may greatlyvary, in general there should be about onequarter A) or one-half /2.) tofifteen (15) parts of blending agent for every part of aluminum salt ofhydrogenated castor oil [or for every part of l2-hydroxy-stearic acid orhydrogenated castor oil]. In some cases the amount ot blending agent maybe in the ratio of three (3) to thirty (30) parts of the blending agentto one (1) part of the material containing the hydroxy fatty acidradical of hydrogenated ricinoleic acid as typified by .the aluminumsoap of hydrogenated castor oil, or said soap containing a smallamount-of 12-hydroxy-stearic acid or l2-hydroxy-stearic acid itself, orhydrogenated castor oil].

only a small percentage of the lead soap. The grease containing the leadsoap of ricinoleic acid is characterized by hardness, a high meltingpoint even in the presence of 'a small percentage of soap, insolubilityin water, and a high film strength, as compared to other greases,including those. greases containing the ordinary lead soap of r castoroil. The lead soap of hydrogenated ricinoleic acid is soluble in theusual lubricant bases, as for example Usually, it is only necessary toincorporate in the grease a small percentage of this soap, as forexample /2 to 2%, with the result that there is produced, even with thislow soap content, a grease that has a high melting point and ischaracterized by water insolubility.

[While it has been stated that the lubricant grease should only containa small percentage of the lead soap of hydrogenated ricinoleic acid,that is from about A to 4%, greases containing are hard greases may beused as block greases on railroad axles, colander bearings, and forother purposes where it is known that a hard grease is necessary ordesirable.

[The following table sets forth greases containing 1%, 2% and 4% of thelead soap of hydrogenated ricinoleic acid, together with the workedpenetration and the meltink point of the resulting greases:

[Mixed soap base greases containing the lead soap of hydrogenatedricinoleic acid, together with other soaps,

were prepared by taking a grease containing 2% of the up to 50% of thissoap which lead soap of hydrogenated ricinoleic acid, as for example thelead soap of hydrogenated castor oil, and mixing therewith a soda basegrease containing 4% of a soda soap. These greases were mixed when coldin various proportions. of the grease containing the lead soap ofhydrogenated ricinoleic acid was mixed with 25% of the soda soap greaseand the grease had a Ubbelohde melting point of 255 F. The final mixedbase grease carried a total soap content of 2 /2%, of which l /z% wasthe lead soap of hydrogenated castor oil and 1% was the ordinary sodasoap. in place of the ordinary soda soap there may be substituted a sodasoap of hydrogenated castor oil. Another grease was prepared by mixing62 /2% of the grease containing 2% of the lead soap of hydrogenatedricinoleic acid with 37 /2% of the grease containing 4% of a soda soap.The final grease which has a Ubbelohde melting point of 300 F. andcarried approximately 3% total soap content, has incorporated thereinapproximately 1% of a lead soap and approximately 2% of the soda soap.

Another grease was made by mixing 25% of the grease containing 2% of thelead soap of hydrogenated castor oil and 75% of the grease containing 4%of the soda soap. The resulting grease which carried 3 /2% total soapcontent and had a Ubbelohde melting point of 205 F. carried /2.% of thelead soap and 3% of the soda soap.

[The above greases were smooth, transparent and of good appearance. Ifthe above mixture of greases are heated above the melting point andcooled, the cat treated greases are much softer and grainier than if thegreases are mixed cold, and in view of the above, it is desired that thegreases be mixed in a cold state, although heat may be employed undersome circumstances.

[Another mixed base soap grease was made by mixing 50% of the greasecontaining 2% of the lead soap of hydrogenated castor oil with 50% or"aluminum stearate grease containing 5% of aluminum stearate. Theresulting grease which contained 1% of the lead soap and 2 /2% of thealuminum stearate soap had a Ubbelohde melting point of 205 F. The twogreases were mixed in the cold to provide a smooth, transparent greaseof good appearance.

[Another mixed soap base grease was prepared by mixing in the cold 50%of a grease containing 2% of the lead soap of hydrogenated castor oilwith 50% of a lime base grease containing 10% of a lime soap. Theresulting grease containing 1% of the lead soap of hydrogenated castoroil and 5% of a lime soap of fatty acids; had a melting point of 205 F.The mixed grease was smooth, translucent and of good appearance. Anothergrease was made by mixing together equal parts of a grease containing/z% of a lead soap of hydrogenated castor oil and a soda base greasecontaining 10 /2% of soda soap. The resulting grease was melted togetherand poured into a pan at 250 F. It was then cooled and found to have amelting point of 356 F. and an A. S. T. M. worked penetration of 240.The grease contained a total soap content of 11%, of which /2% was alead soap, and the remainder was the soda soap. The free alkali contentof the resulting grease, as determined by the regular A. S. T. M. methodwas 08%, and the grease had a Saybolt oil viscosity of 500 seconds at F.When rolled in ball bearings, it retained the same approximateconsistency for a working time of two hours] Greases may be preparedcontaining the alkali earth soaps of hydrogenated ricinoleic acid suchas castor oil. More specifically, there may be dissolved andincorporated in the mineral oil 1 to. 8% of calcium soap of hydrogenatedcastor oil; or 1 to 8% of the strontium soap of hydrogenated castor oil;or 1 to 8% of the barium soap of hydrogenated castor oil. These soapsare dssolved and incorporated in the mineral oil at a temperature of350, and on cooling the soap separated from the oil. However, if thegrease is reheated at a suitable temperature, as

Ti 1 of water based on the weight of the grease, an emulsion is formedand solid greases are obtained on cooling.

[There may also be dissolved, dispersed and/or incorporated in a greasehaving a mineral, vegetable oil, or animal base, 1 to 5% of one or moreof the metal soaps of hydrogenated ricinoleic acid of the followingmetals: magnesium, tin, nickel, cobalt, chromium, and manganese.

All of these soaps go into solution in the mineral oil at temperaturesbelow 300 F. The greases were permitted to cool by placing them in anelectric oven maintained at 260 F., cutting off the current andpermitting the greases to slowly cool at room temperature in 8 to 10hours. The grease containing the nickel soap of hydrogenated ricinoleicacid, as for example castor oil, yielded a soft gel, but the othergreases were of a more fluid viscous consistency. These greases of afluid consistency exhibited properties which make them adaptable formany lubricating purposes.

[While the present invention in its preferred form is directed to theproduction of greases in a solid form and desirably having a low soapcontent with a high melting point, the invention is not limited theretoand includes the production of liquid lubricating mediums, includingfluid viscous lubricants adaptable for use in connection with thelubrication of Diesel engines. Such fluid lubricants may also be used astransmission oils, motor oils, and the like.

[While it has been specified that the soap of hydrogenated castor oilwhich is used is the metal soap, it is within the province of thepresent invention, in some cases, to substitute for the metal base anorganic radical to produce an organic soap. For example, instead ofusing a metal constituent, the hydrogenated fatty acid may be combinedwith ethanolamine to produce an amine soap which when incorporated inthe lubricating greases, especially the fluid viscous lubricants givesdesirable results.

[The soda soap of hydrogenated ricinoleic acid, as for example castoroil, may be formed directly in a mineral oil such as was used for theproduction of the soaps immediately above described, said oil having a300 viscosity at 100 Saybolt. The sodium soap of hydrogenated castor oilmay be made by the direct saponification of hydrogenated castor oilpresent in the mineral oil. After the saponifying caustic soda has beenadded, the temperature is, raised to 350 F., and the mixture heatedduring saponification to drive off substantially all of the moisture.The resulting grease is smooth, pliable and has aworked A. S. T. M.consistency of 350 to 375 and contains 8% of sodium soap.]

While in the majority of cases the herein described soaps may bedispersed in a mineral oil base, it is obvious that the mineral oil basemay have mixed therewith any of the well known lubricating basesincluding hydrogenated fish oil, animal oils, vegetable oils, and rosinor a plurality thereof.

As previously pointed out, the soap which is incorporated in the greasein accordancewith the present invention may in one form of the inventionbe a soap of hydrogenated ricinoleic acid which, as stated, may betermed a l2-hydroxy-stearic acid. This designation, in accordanee withthe common usage, means that the hydroxy group is on the twelfth carbonatom from the carboxyl group.

[In accordance with the present invention, the lubricating medium as,for example, a grease, may have incorporated therein a soap of aIO-hydroxy-stearic acid, as for example the lead soap of this acid. Thisproduct may be manufactured by several accepted methods of preparation,including a metathesis reaction utilizing a soluble lead salt such aslead acetate in reaction with the sodium soap of the lO-hydroXy-stearicacid. The lead soap of the whydroxy-stearic acid has a somewhat softertexture and a lower solubility in the mineral oil bases in which thelead soap of the l2-hydroxy-stearic acid was incorporated. Further, thelead soap of the IO-hydroxystearic acid does not gel and/ or harden thegrease in which is incorporated to the same optimum degree as that whichoccurs when the lead soap of the IZ-hydroXy-stearic acid, the acid ofwhich has been produced by acid or by other means, is incorporated inthe grease.

[In accordance with the present invention there may also be incorporatedin a lubricating medium soaps of the poly-hydroxy-stearic acids. Forexample, the soaps may be formed from hydroxy-stearic acids in which thel1ydroxy groups are in the 9 and 10 carbon position. The polyhydroxystearic acid may be prepared by oxidation and subsequent hydroxylizationof oleic acid. The soaps of this acid may be prepared by metathesis, asabove set Forth, and by direct combination of the above fatty acid withoxides of metals as, for example, heating the fatty acid dispersed in ahydrocarbon oil to which there has been added a metal constituent, asfor example lead oxide or litharge. While the methathesis method and theabove method produce slightly ditferent end products, the generalbehavior is substantially the same.

[In accordance with the present invention, the lubricating medium mayhave incorporated therein lead, aluminum, or sodium soaps of polyhydroxystearic acid, said soap being produced by .the metathesis or doubledecomposition method. The sodium soap produced, as above set forth, wasonly slightly soluble in the mineral oil base and was soluble even withdifliculty at 400 F. Therefore, it is necessary when incorporating thisproduct to provide for a carrier much in the same manner as when thealuminum soap of ricinoleic acid is incorporated in a lubricant base.

[The aluminum soap of the 9 and 10 dihydroxy-stearic acid also wasslightly soluble in the hydrocarbon oil, preferably at temperaturesapproximating 400 F.

[The lead soap of this dihydroxy-stearic acid, the hydroxy groups beingin the 9 and 10 position, was prepared by the methods above set forth,and its properties were substantially parallel to that of the sodium andaluminum soap above set forth, execept that it was more soluble -in thehydrocarbon base and the solubility was better at 300 F. On heating to ahigher temperature there was some degradation of the lead soap whichresulted in a grease which on cooling possessed the characteristics of agrease showing a low solubilized content of lead soap] [From the aboveit appears that] The presence of more than one hydroxy group in ahydroxy-stearic acid soap reduces'the solubility of metal soaps thereofin the lubricant base. Because of this reduced solubility, these soapsshould preferably be added to the lubricant base in amounts under 1%,although when a carrier is used the amounts may be increased. However,it is desired to point out that the soaps of the polyhydroxy-stearicacids, as a class, exhibit inferior jellying characteristics as far astheir effects upon the mineral oil base is concerned.

[It is desired to point out that irrespective of whether the lubricatingmedium is a grease or a viscous non-solid lubricating medium, it mayhave incorporated therein a mixture of a metal soap of a mono orpoIyhydroxy-stearic acid, together with an organic soap of a mono orpolyhydroxy-stearic acid. In other words, instead of having a metalcoupled to the acid constituent, the hydroxystearic acid may havecoupled thereto an organic base. In the more specific aspect of theinvention] The metal soap of the l2-hydroXy-stearic acid which is hereintermed the metal soap of hydrogenated ricinoleic acid, may have mixedtherewith an organic soap of the IZ-hydroxy-stearic acid.

[In general it may be stated that in the lubricating medium hereindisclosed, all or part of the metal soap of any of the hydroxy-stearicacids herein set forth may have all or part of the metal soapsubstituted by a soap made by saponifying a hydroxy-stearic acid with anorganic base to produce .what may be termed an organic soap] 13Referring to the preparation of greases which contain the aluminum soapsof hydrogenated ricinoleic acid, together with a carrier for the same,it is desired to point out that the aluminum soaps of stearic acid andthe aluminum soaps of the hydrogenated ricinoleic acids may be cookedtogether to thereby provide a much better dispersablc produce. In otherwords, the solubility of the aluminum soap of the hydrogenatedricinoleic acid is greatly improved due to the fact that one or more ofthe bonds of the aluminum contains or is coupled up with stearic acid,while the other bond is coupled up or contains hydrogenated ricinoleicacid.

It is desired to point out that in general the lubricants, including thegreases, may have present [an organic soap of any of the hydroxy-stearicacids, including the monohydroxy-stearic acid and thepolyhydroxy-stearic acids, and more specifically] any of the hereinmentioned metallic metal soaps, including aluminum [sodium] barium,

[lead] strontium, calcium, magnesium, [tin, nickel, co- 1 balt,chromium, manganese,] and the like, or the lubricant including greasesmay have incorporated therein a plurality of any of the herein describedsoaps to thereby produce a mixed base lubricant.

The following illustrates the production of greases using an aluminumstearate grease which did not have incorporated therein a soap ofl2-hydroxy-stearie acid [or other equivalents, hydrogenated castor oil,or 12-hydroxystearic acid itself, and greases in which in one case thereis incorporated hydrogenated castor oil, and in another caseIZ-hydroXy-stearic acid. In one case] a mixture was made of 6.8%aluminum stearate and 93.2% of a mixed paraflin and asphalt base oilhaving 180 Saybolt viscosity at 100 F. The resulting grease had an ASTMworked penetration of 298 and was characterized by graininess andsubstantial seepage of oil.

[Another lubricant was compounded having 6.8% aluminum stearate, 92.7%of the same oil base, and 5% of hydrogenated castor oil. The resultinggrease had a worked penetration of 331. The grease instead of beinggrainy was smooth and showed substantially no oil sep aration. Anothergrease was compounded, using 6.8% of aluminum stearate, 92.7% of thesame oil base, and .5% of free fatty acid of hydrogenated castor oil, or12- hydroxy-stearic acid. The resulting grease was transparent and hadan ASTM worked penetration of 334. The resulting grease was smooth andshowed no oil separation.]

Instead of using an aluminum stearate in the above examples, otheraluminum salts of saturated and unsatu-- rated fatty acids may be used.

This application is a continuation-in-part of application Serial No.347,533, filed July 25, 1940, said application being acontinuation-in-part of application Serial No. 268,781, filed April 19,1939, both now abandoned.

I claim:

1. A lubricating grease containing a lubricant base together with acalcium soap of [a] 12-hydroXy-stearic acid [together with a blendingagent therefor].

[2. A lubricating grease containing a lubricant base together with ametal soap of a 12-hydr0Xy-stearic acid together with a blending agenttherefor] [3. A lubricating grease containing a lubricant base togetherwith a soap of 12-hydroxy-stearic acid] 4. A lubricating greasecontaining a lubricant base together with [a] an alkaline earth metalsoup of 1?.- hydroxy-stearic acid.-

5. A lubricating grease containing a lubricant base together with acalcium soap of hydrogenated ricinoleic acid.

[6. A lubricating grease containing a lubricant base together with 1 toof a soap of hydrogenated ricinoleic acid] 7. A lubricating greasecontaining a lubricant base together with an alkaline earth [a] metalsoap of hydrogenated ricinoleic acid.

8. A lubricating grease containing a lubricant base together with 1 to10% of an alkaline earth [a] metal soap of hydrogenated ricinoleic acid.

[9. A lubricating grease containing a lubricant base and havingdispersed therethrough a metal soap of hydrogenated ricinoleic acidtogether with a blending agent therefor] [10. A lubricating greasecontaining a lubricant base, said grease having its normal texturemodified by the presence of a metal soap of hydrogenated ricinoleic acidacting as a granulation inhibitor] 11. A lubricating grease containing alubricant base together with an aluminum soap of hydrogenated ricinoleicacid in an amount adapted to inhibit granulation of the grease.

12. A lubricating grease containing a lubricant base together with analuminum soap of IZ-hydroxy-stearic acid in an amount adapted to inhibitgranulation of the grease, and a carrier for said granulation inhibitor.

13. A lubricating grease containing a lubricant base together with analuminum soap of hydrogenated ric inoleic acid in an amount adapted toinhibit granulation of the grease, and a metal soap of a fatty acidhaving at least twelve carbon atoms, said metal soap functioning as acarrier and blending medium for said granulation inhibitor.

14. A lubricating grease containing a lubricant base together with analuminum soap of hydrogenated ricinoleic acid in an amount adapted toinhibit granulation of the grease, and an aluminum soap of a fatty acidhav ing at least twelve carbon atoms, said aluminum soap functioning asa carrier and blending medium for said granulation inhibitor.

15. A lubricating grease containing a lubricant base together with from4% to 10% of an aluminum soap of hydrogenated ricinoleic acid, and ametal soap of a fatty acid having at least twelve carbon atomsfunctioning as a carrier and blending agent for said aluminum soap.

16. A lubricating grease containing a lubricant base together with fromto 10% of an aluminum soap of hydrogenated ricinoleic acid, and analuminum soap of a fatty acid having at least twelve carbon atoms, thelatter functioning as a carrier and blending agent for said aluminumsoap of hydrogenated ricinoleic acid.

17. A lubricating grease containing a lubricant base together with A to5% of an aluminum soap of hydrogenated ricinoleic acid and a carrieradapted to permanently disperse and incorporate the aluminum soap in thelubricating grease, the carrier being present in the ratio of three tothirty parts to one part of said aluminum soap.

18. An aluminum base grease having incorporated therein /z% to 5% of thealuminum soap of hydrogenated ricinoleic acid.

19. An aluminum base grease having incorporated therein aluminumstearate and from /2% to 5% of the aluminum soap of hydrogenatedricinoleic acid.

20. A soda base grease having incorporated therein logo to 5% of analuminum soap of IZ-hydIoXy-stearic aci 21. A soda base grease havingincorporated therein sodium soaps of fatty acids, sodium rosinate, and asmall percentage of an aluminum soap of 12-hydroxy-stearic acid, thelatter functioning to stabilize the grease and prevent oil leakage.

22. A soda base grease having incorporated therein fatty acid soaps,sodium soaps, a hardening agent, a small percentage of an aluminum soapof hydrogenated ricinoleic acid, the latter functioning to stabilize thegrease and prevent oil leakage, and a carrier and blending agent forsaid aluminum soap.

1 5 about four percent (4%) of fatty acid sodium soap, less than onepercent (1%) of a hardening agent, less than one percent (1%) of analuminum soap of hydrogenated ricinoleic acid, the latter functioning tostabilize the grease and prevent oil leakage, and less than one percent(1%) of a carrier and blending agent for said aluminum soap.

24. A soda base grease having incorporated therein up to four percent(4%) of fatty acid sodium soap, a hardening agent, one-quarter A to fivepercent (5 of an aluminum soap of hydrogenated ricinoleic acid, thelatter functioning to stabilize the grease and prevent oil leakage, anda carrier and blending agent for said aluminum soap, the former beingpresent in the ratio of A to 15 parts to one part of the aluminum soap.

25. A lubricating grease containing a lubricant base and an insitu-formed mixture of an aluminum soap of hydrogenated ricinoleic acidand a blending agent for said aluminum soap.

26. The method comprising inhibiting granulation of a lubricating greaseby adding thereto a small proportion of an aluminum soap of hydrogenatedricinoleic acid.

27. The method comprising inhibiting granulation of a lubricating greaseby adding thereto a small proportion of an aluminum soap of hydrogenatedricinoleic acid together with a carrier for said soap capable ofpermanently dispersing said soap in the lubricant base.

28. The method of forming a lubricating grease comprising mixing analkaline earth metal base soap of 12- hydroxy-stearic acid with an oilbase, heating the resulting mixture in the presence of water adapted toproduce an emulsion, and cooling whereby a solid grease containing saidsoap is produced.

' of IZ-hydroxy-stearic acid whereby the dispersibility of the resultingsoap in the grease is greatly improved.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS 2,283,602 Fiero May 19, 1942 l FOREIGN PATENTS157,953 Switzerland Jan. 2, 1933

